There are many definitions of the term “powder”, from a crude distinction of particles with small grain size as powders and those with larger ones as granulars, to appellations like particulate matter and microparticles. The fields of technology dealing with the physical properties, measuring methods and operating procedures of such powders, i.e. aggregates of multiple particles, are similarly referred to as particulate technology or microparticle technology, depending on the type of powder in question.
Powders are mainly solid matter composed of fine particles, and are used in a wide variety of technical fields, including, for example, the food industry (wheat flour etc.), the chemical industry (cosmetics, pharmaceuticals etc.), application of powder to surfaces (powder coating), and surface processing using powders (polishing, chemical reactions etc.). Such powder aggregates have unique properties that differ from those of liquids, gases, and solids, and are well known to easily cause problems in production processes and in the aforementioned fields such as sticking, scattering, and blockage.
In the field of thermal spraying, in which for example metallic powder is heated to a molten state by a high-temperature gas and sprayed onto a target surface to form a coating, powder feeders such as the ones described in Patent Document 1 or Patent Document 2 have been proposed.